ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 377 



the cells varies considerably in the different habitats. The bristles (seta 

 in Hnber's sense) are homologous with branch cells, and arise singly 

 or in pairs on every cell. The zoospores vary much in their form. The 

 escape of the zoospores takes place through the bristles, a stopper being 

 thrust out from the apex. The occurrence of gametes has not been 

 observed, and Hauck's statement as to the copulation of swarm-spores 

 does not hold good. Coloured plates show habit and detailed structure. 



E. S. Ct. 



Cytology of the CladophoraceaB. — Nellie Caeter {Ann. of Bot.y 

 33, 1919, 467-78, 1 pi. and figs.). In Cladophora, Chsetomorpha., and 

 Rhizodoni'.im the chloroplast consists invariably of a parietal film lining 

 the cell-wall, and often more or less reticulated in proportion to the cell- 

 contents ; in well-nourished cells numerous trabeculte traverse the lumen. 

 Pyrenoids are numerous in both peripheral and internal parts of the 

 chloroplast. The nuclei are mostly confined to the chloroplast, rarely 

 occurring in the colourless cytoplasm, which layer is difficult to detect. 

 The nuclei are proportionately large in some narrow forms of Rhizo- 

 clonium, and may project from the chloroplast into the cavity of the cell. 

 The nuclei in R. hierogJijphicum are more numerous than was formerly 

 believed, and in thick forms they frequently are as many as twenty-four 

 in a cell. In autumn much starch is stored as small grains lodged in the 

 interstices of the chloroplast-reticulum, thus distending the chloroplast. 

 During mitosis the nucleus of Rhizodonium and Cladophora is cha- 

 racterized by a long thin spireme and very numerous chromosomes. 

 After the migration of the latter to opposite poles of the spindle the 

 daughter-nuclei are separated by constriction of the spindle in the region 

 of the equator. A. G. 



New Nitella.— G. R. Bullock- Webster {Joiim.of Bot., 1919, 57, 

 1-2, 1 pi.). A description and figures of a new species of Nitella, from 

 a lake near Kindrum, in the Fanad Peninsula of County Donegal. 

 N. spaniodema is a delicate fragile species, abundant in the lake, and 

 remarkable for its depauperate ramification and other peculiarities. It is 

 closely allied to N. flexilis. A. G. 



Chara fragilis and C. delicatula.— J. Groves and G.R. Bullock- 

 Webster {Journ. of Rot., 1919, 57, 69). A note on the structural 

 characters which justify the separation of C. delicatula as a distinct 

 species from C. fragilis. The former plant has well-developed stipulodes, 

 and has its primary cortical-cells wider than the secondary cells, and 

 discernible spine-cells. A. G. 



Notes on Lychnothamnus. — James Groves (/(9?<rn. of Boi., 1919, 

 57, 125-9). A discussion of the distinctive characters of the genus, 

 and a consideration of certain species that have been referred to it. One 

 of the latter, L. stelUger, has been made the type of Nitellopsis Hy., and 

 its synonomy is now revised. As to L. macropogon, the question is 

 considered whether it should be transferred to Lamprothamnion or to a 

 separate genus, 3Iacropogo7i, or, as the author prefers, back again to 

 Chara. This leaves in Lydmothamnus the one well-marked species,. 

 L, harhatus. A. G. 



